The goal is to manually import all the road segments not yet present in OSM, joining them with the existing highways.

For this purpose, a detailed workflow will be followed by all users involved in this task.

Schedule

Preparation, discussion - due to start February 9th 2015.

Import - expected to start any time after the community has solved any issues, doubts or concerns about this import.

Import Data

Data description

The original data is in shapefile format. The accuracy of the data varies: some segments are quite correct and can be imported with little correction, whereas some others have to be corrected manually before upload or being used as a guide to map the actual road.

Methodologies for production process of source data was the same across all congo basin countries. Detailed on the origin and production process for the source data can be found here.

Original tags vary for each country, but are quite similar. The proposed OSM tagging tries to keep consistency across all the countries.

Import Type

As the quality of the data varies, some ways can be imported with few corrections, but others will rather be used as a guide for tracing a more accurate one, transferring the tags from the WRI segment to the new one. Incorrect segments or segments will be ignored (deleted), whereas segments that overlap with OSM data will be conflated.

The import will be carried out by users who will read and understand the workflow wiki set for this import. For each of the 6 countries, the process will be done with the help of a HOT Tasking Manager project, where every mapper will download the OSM data and the WRI data into two different layers, so they can correct the WRI data and conflate it with the OSM data before they upload it to the OSM database.

Data Preparation

Data Reduction & Simplification

The data is originally in shapefile format, in only one file for each of the 6 countries. You can download the original files here.

From this files, we extracted the forestry relevant data. We further deleted all segments that have been already mapped in OSM.

Data has been corrected of errors, duplications, overlaps, etc., but it will be checked again during the import process.

11 values: if 0.0 or 10431.0 or 206.0 not imported, if 2004.0 YYYY=2005, if 2005.0 YYYY=2006, if 2006.0 YYYY=2007, if 2007.0 YYYY=2008, if 2008.0 YYYY=2009, if 2011.0 YYYY=2012, if 2012.0 YYYY=2013, and if 2013.0 YYYY=2014

where imageryProvider=Bing, Mapbox or whatever imagery used while importing the data, NUMBEROFPROJECT being the Tasking Manager project number and NAME_OF_COUTRY be substituted by the country code: CMR for Cameroon, GNQ for Equatorial Guinea, etc.

Data Transformation

Each of the 6 files in shapefile format were opened with JOSM + Open Data plugin, and saved in osm format. After this, each one was transformed into a new osm file with the proposed tags, using an ad-hoc awk script for each one.

Data Merge Workflow

Team Approach

Import will be undertaken by mappers trained for this task, using an import specific OSM user account and following a [WORKFLOW LINK detailed workflow with screenshots], that shows all the steps to follow, with the goal of best keeping the consistency and correctness during all the process.

Workflow

1. In areathat will be s with high resolution aerial imagery, users will check the accuracy of each segment against that imagery, and will correct it or trace a new one using the WRI segment as a guide if accuracy is poor.

2. Conflating with the existing OSM highways: As explained before, the roads in the WRI dataset that conflict with others already in OSM have been removed already. If one user finds a segment conflicting with an OSM highway, he/she will check which one is more accurate. In case the OSM way is better, s/he will combine the WRI way tags into the existing OSM counterpart. Otherwise, the OSM way will be replaced with the WRI, keeping the OSM way history.

3. Users involved in this import will validate the data to be imported, and correct the errors they may still have. Typical ones are duplicated nodes, not connected highways in crossroads, two close parallel segments that should be only one, very short few-metres segments that should be deleted, etc.

The workflow will follow these general steps:

1) One of the importing users chooses one of tasks of one of the Tasking Manager projects (there is one for each country).

2) S/he downloads the OSM data in one layer, and the WRI data for that tile in a different layer.

3) S/he then opens the aerial imagery layers we have for that area. In case there are enough GPS traces, s/he can align the imagery layers.

4) S/he then corrects the errors in the WRI data layer, like duplicated nodes, crossing ways and ways not joined to each other. Those ways that are wrong will be corrected or, in some cases, deleted and not imported. If there is any segment already present in OSM, we will conflate them as it was already explained.

5) Next, we will merge the WRI data layer with the OSM data layer and proceed to join and combine ways to finish the task.

6) Before we consider the task finished, we will check once again for any errors and warnings in the merged layer. New errors that may appear are lack of bridges or fords in river crossings.

7) Last, we upload the data with the special OSM import account.

Reverse plan

In case of any trouble, JOSM reverter will be used.

Conflation

Conflation has already been explained in the workflow section above. It will deal mainly with joining WRI roads to other OSM roads.